Mitre boxes are widely employed for cutting workpieces at various angles other than right angular or with precise straight cuts, particularly in cabinet making, in framing of door openings and the like, and in making moldings. Various constructions are used and have been proposed for mitre boxes varying from simple channel-shaped structures having guide cuts or slots in their opposed walls to very complex and expensive structures providing a pair of guide posts which receive the saw and one (or both) of which may be moved along the mitre box bed relative to the other to establish the desired angular relationship of the saw relative to guide surfaces against which the workpiece is placed.
Another type of mitre box is one in which a pair of saw guide elements are rotatably supported upon a single post and may be rotated thereabout to establish the desired angular relationship of the saw carried thereby relative to the guide surface and the workpiece. To maintain the saw guide elements in the desired position, they must be locked in the desired rotated position on the post after they have been rotated, and several mechanisms have been proposed therefor. One of the most useful means is a wedge which is movable into and from engagement with detents on a member which is a part of the support structure for the saw guide elements and which is rotatable about the post.
It will be appreciated that any deviation of such a wedge from an axis lying in the plane of the post about which the saw guide elements are rotated will result in a variation of the saw kerf from the desired angular relationship. Moreover, if the elements are not rigidly locked, there is a tendency for the saw to wander and create an uneven kerf.
Another problem that may be encountered when the saw guide members are supported from a common post is a tendency for some variations in spacing to occur between the saw guide elements at the points which restrain the sidewise motion of the saw. As a result, it is possible for the saw to have undesired sidewise motion at one end of the guide elements and to be subject to excessive pressure at the other end, making the sawing action difficult.
It is an object of the present invention to provide a novel mitre box using a novel saw guide assembly providng advantageous control of the pressure on the saw received therein.
It is also an object to provide such a mitre box in which the elements may be fabricated readily and relatively economically, and in which the pressure exerted upon the saw by clamping the saw guide members together may be readily adjusted and more closely balanced between the ends thereof.